Slow and easy, kids come first, try to always take the high road...
Before you know it, you'll save a few dollars and then you'll build something like ours:
7x16 cargo trailer conversionedit: and here it is with the removable A/C addition:
Window A/C additionThis idea started with a small trailer just to take our camping gear and then well, you know how it goes.
We even use it for day trips kayaking and mountain biking for the convenience.
You could easily downsize the project to fit the Hummer and the budget